A resonant hole length adjustable muffler shell, compressor and muffling method

Abstract

The application provides a resonant hole length-adjustable muffler shell, a compressor and a muffling method, and relates to the technical field of compressor noise reduction.The resonant hole length-adjustable muffler shell, the compressor and the muffling method have the following characteristics: a first cavity is arranged between an upper inner shell and an upper outer shell, a through hole is arranged in the upper inner shell, a first resonant pipe and a second resonant pipe are arranged, the through hole, the first resonant pipe and the second resonant pipe form a resonant hole, the first cavity forms a Helmholtz resonant type sound attenuation cavity, and the Helmholtz resonant type sound attenuation cavity is used for realizing muffling; the second resonant pipe can be axially extended or retracted by a set length relative to the first resonant pipe, so as to adjust and change the length of the resonant hole; the length of the resonant hole is adjusted and changed to change the muffling frequency, the real-time muffling frequency is matched with the cavity noise peak frequency generated by the excitation of the multiple harmonic peak value corresponding to the real-time rotating speed of the compressor, and the muffling and noise reduction are realized.

Description

Technical Field

[0001] This invention relates to the field of compressor noise reduction technology, specifically to a noise-reducing housing with adjustable resonant hole length, a compressor, and a noise reduction method. Background Technology

[0002] The compressor noise mainly comes from the noise inside the casing and the noise radiated by the vibration of the casing.

[0003] Internal noise includes valve plate slapping noise, refrigerant high-speed flow and ejection noise, structural component friction noise, electromagnetic noise, and structural component vibration noise, among which intake and exhaust valve plate slapping noise and refrigerant high-speed flow and ejection noise in cylinder and cylinder head components account for the highest proportion.

[0004] Because the compressor uses indirect suction, the intake port of the suction muffler is not directly connected to the housing, but rather to the internal cavity of the housing. Valve plate slapping noise, refrigerant high-speed flow and ejection noise, and suction pressure pulsation are transmitted to the internal cavity of the housing through the suction muffler. While the suction muffler can reduce some noise and pulsation, it still excites a response within the internal cavity. This internal cavity is a closed structure and contains acoustic modes. These modes vary with the cavity volume and size, with the first three modes contributing the most, falling within the 630-1000Hz range. Smaller volumes result in higher frequencies. Under the excitation of noise and pulsation, resonance occurs, amplifying the noise and generating cavity resonance noise.

[0005] The noise and pulsating excitation of a reciprocating piston compressor are both harmonics of the fundamental rotational frequency. Therefore, the harmonics of the fundamental frequency will inevitably cover the entire frequency band across the entire compressor speed range. There will inevitably be excitation peaks near the modal frequencies of the housing cavity, thereby exciting resonance. Therefore, cavity resonance noise is an inherent property of compressor noise and cannot be eliminated. Currently, the only way to reduce noise excitation is to optimize the silencer.

[0006] The noise radiated by the shell vibration comes from the vibration response generated by the vibration of the shell due to the vibration of the mechanism, which radiates outward noise, and from the vibration generated by the acoustic-vibration coupling of the shell due to the noise inside the shell, which radiates outward noise. Summary of the Invention

[0007] The purpose of this invention is to provide a noise reduction housing, compressor and noise reduction method with adjustable resonant hole length, which reduces cavity resonance noise by reducing cavity volume and achieves adaptive noise reduction across the entire speed range by changing the resonant hole length.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A sound-absorbing housing with adjustable resonant hole length includes an upper outer shell, an upper inner shell, a lower shell, a first resonant tube, a second resonant tube, and a driving device.

[0010] The upper inner shell is located inside the upper outer shell, the edge of the upper inner shell is connected to the edge of the upper outer shell, and a first cavity is left between the upper inner shell and the upper outer shell;

[0011] The edge of the upper outer shell and / or the edge of the upper inner shell mates with the edge of the lower shell, and a second cavity is left between the upper inner shell and the lower shell;

[0012] The upper inner shell has a through hole, which connects the first cavity and the second cavity;

[0013] The first resonant tube is provided on the upper inner shell, and the first resonant tube is connected to the through hole;

[0014] The second resonant tube is nested between the first resonant tube and the second resonant tube is slidably fitted with the first resonant tube along the axial direction, and the second resonant tube can extend or retract relative to the first resonant tube along the axial direction.

[0015] The drive device is activated to cause the second resonant tube to extend or retract a set length relative to the first resonant tube along the axial direction.

[0016] Preferably, a limiting strip is provided on the first resonant tube along the axial direction, and a limiting groove is provided on the second resonant tube along the axial direction, wherein the limiting strip slides into the limiting groove.

[0017] Preferably, the first resonant tube is nested inside the second resonant tube, and the outer wall of the second resonant tube has a spiral groove along the axial direction;

[0018] The driving device is a motor, and the rotating end of the motor is provided with a protrusion;

[0019] The motor is mounted on the upper inner shell, and the protrusion cooperates with the spiral groove;

[0020] The rotating end of the motor rotates forward or backward by a set angle to drive the second resonant tube to extend or retract a set length relative to the first resonant tube along the axial direction.

[0021] Preferably, the upper inner shell has several protrusions and recesses on one side of the second cavity.

[0022] Preferably, the outer contours of the protrusion and the recess are stepped.

[0023] Preferably, the edge of the upper inner shell mates with the edge of the upper outer shell, and an annular groove is provided at the edge of the lower shell, with the edge of the upper outer shell fitting into the annular groove.

[0024] A compressor includes a core assembly, a frequency converter, and a controller.

[0025] The compressor is equipped with a sound-absorbing housing with an adjustable resonant hole length. The core assembly is located inside the second cavity. The controller is connected to the frequency converter and the drive device via signal cables. The controller controls the operation of the drive device according to the output frequency of the frequency converter.

[0026] A method for reducing noise in a compressor, using the compressor described above.

[0027] The controller stores "the peak frequency of cavity noise generated by the peak excitation of the harmonic peak of the fundamental frequency corresponding to the compressor speed", "the quantitative relationship between the compressor speed and the inverter output frequency" and "the silencing frequency corresponding to the second resonant tube extending or retracting a set length along the axial direction relative to the first resonant tube".

[0028] The method includes the following steps:

[0029] When the compressor is running, the controller reads the real-time output frequency of the inverter to obtain the real-time speed of the compressor, and then obtains "the peak frequency of the cavity noise generated by the peak excitation of the harmonic peak of the fundamental frequency corresponding to the real-time speed of the compressor".

[0030] The controller controls the drive device to extend or retract the second resonant tube relative to the first resonant tube along the axial direction by a set length, so that the real-time noise reduction frequency matches the peak frequency of the cavity noise generated by the excitation of the harmonic peak of the fundamental frequency corresponding to the real-time rotational speed of the compressor.

[0031] The beneficial technical effects of this invention are:

[0032] The present invention relates to an adjustable resonant hole length silencing housing, compressor, and silencing method. By setting a first cavity, the volume of the second cavity is reduced. This reduction in the volume of the second cavity increases the cavity modal frequency of the second cavity, preventing the fundamental harmonics from resonating near their lower peak frequencies near the cavity modal frequency. The first cavity is positioned between the upper inner shell and the upper outer shell. A through-hole is formed in the upper inner shell, and a first resonant tube and a second resonant tube are installed therein. The through-hole, the first resonant tube, and the second resonant tube constitute a resonant hole, making the first cavity a Helmholtz resonant silencing cavity. Noise reduction is achieved through a Helmholtz resonant silencing cavity. The second resonant tube can extend or retract by a set length relative to the first resonant tube along the axial direction to adjust the length of the resonant hole. By adjusting the length of the resonant hole, the silencing frequency is changed, so that the real-time silencing frequency matches the peak frequency of the harmonic of the fundamental frequency corresponding to the real-time speed of the compressor, thus achieving noise reduction. In addition, the upper inner shell forms several protrusions and recesses on the side of the second cavity to achieve refractive noise reduction. In addition to refractive noise reduction, sound insulation is further achieved through the upper inner shell and then through the upper outer shell. Thus, through the reduction of cavity resonance noise, resonance silencing (the silencing frequency can be adjusted), refractive noise reduction, sound insulation of the upper inner shell and the upper outer shell, the compressor achieves a good noise reduction effect. Attached Figure Description

[0033] Figure 1 A cross-sectional view of the compressor according to an embodiment of the present invention. Figure 1 ;

[0034] Figure 2 A cross-sectional view of the compressor according to an embodiment of the present invention. Figure 2 ;

[0035] Figure 3 This is an exploded view of the outer shell, inner shell, valve assembly, and drive device according to an embodiment of the present invention;

[0036] Figure 4 This is a cross-sectional view of the outer shell, inner shell, first resonant tube, second resonant tube, and driving device according to an embodiment of the present invention.

[0037] Figure 5 for Figure 4 A magnified view of a section at point A in the middle;

[0038] Figure 6 The three-dimensional inner shell of the embodiment of the present invention Figure 1 ;

[0039] Figure 7 The three-dimensional inner shell of the embodiment of the present invention Figure 2 ;

[0040] Figure 8 This is a bottom view of the inner shell in an embodiment of the present invention. Detailed Implementation

[0041] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. Certain embodiments of the invention will be described more fully below with reference to the accompanying drawings, and some, but not all, of these embodiments will be shown. In fact, various embodiments of the invention can be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to enable the invention to meet applicable legal requirements.

[0042] In the description of this invention, it should be noted that the terms "inner," "outer," "upper," "lower," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0043] In this embodiment of the invention, a sound-absorbing housing with adjustable resonant hole length, a compressor, and a sound-absorbing method are provided. Please refer to [reference needed]. Figures 1 to 8 As shown.

[0044] A sound-absorbing housing with adjustable resonant hole length includes an upper outer shell 11, an upper inner shell 12, a lower shell 2, a first resonant tube 31, a second resonant tube 32, and a driving device 4.

[0045] The upper inner shell 12 is located inside the upper outer shell 11, and its edge connects to the edge of the upper outer shell 11. A first cavity 51 is provided between the upper inner shell 12 and the upper outer shell 11. The upper outer shell 11 and the upper inner shell 12 are formed by stamping steel plates using a stamping process. The upper outer shell 11 is thicker than the upper inner shell 12, and the total thickness of the upper outer shell 11 and the upper inner shell 12 is the same as the thickness of the lower shell 2. The external shape and dimensions of the upper outer shell 11 and the lower shell 2 remain unchanged, without affecting the overall height and size of the compressor, achieving compatibility with end product designs (such as refrigerators) and reducing costs.

[0046] The edge of the upper inner shell 12 is interference-fitted with the edge of the upper outer shell 11 to achieve a tight connection between the edges of the upper inner shell 12 and the upper outer shell 11. The edge of the upper inner shell 12 is stacked on the inner wall of the upper outer shell 11, and the outer wall of the edge of the upper outer shell 11 mates with the edge of the lower shell 2. A second cavity 52 is provided between the upper inner shell 12 and the lower shell 2. Specifically, an annular groove 21 is provided at the edge of the lower shell 2, and the edge of the upper outer shell 11 fits into the annular groove 21, thereby assembling and fixing the upper outer shell 11 and the lower shell 2. In this way, the annular groove 21 of the lower shell 2 limits and squeezes the edge of the upper inner shell 12 and the edge of the upper outer shell 11, so that the edge of the upper inner shell 12 and the edge of the upper outer shell 11 are firmly fitted together.

[0047] By setting the first cavity 51, the volume of the second cavity 52 is reduced, the cavity mode frequency of the second cavity 52 is increased, and the harmonics of the fundamental frequency are prevented from resonating near the cavity mode frequency of the second cavity 52 at a lower peak frequency, thereby reducing cavity resonance noise.

[0048] Compressor speeds are typically 1200-4500 rpm, corresponding to a fundamental frequency of 20-75 Hz. For example, when a compressor runs at 3000 rpm, the fundamental frequency is 50 Hz. There are integer multiples of 50 Hz peaks throughout the entire frequency range, such as 100 Hz, 150 Hz, 200 Hz, and 250 Hz. As the peak frequencies of the fundamental frequency's harmonics increase, their corresponding excitation energy decreases. This allows the higher peak frequencies of the fundamental frequency's harmonics to resonate near the cavity's modal frequency, resulting in lower resonance energy and reduced cavity resonance noise.

[0049] The upper inner shell 12 has a through hole 121, which connects the first cavity 51 and the second cavity 52. ​​A first resonant tube 31 is provided on the upper inner shell 12 and is assembled in the through hole 121. The first resonant tube 31 is connected to the through hole 121. The second resonant tube 32 is nested between the first resonant tube 31 and the second resonant tube 32.

[0050] A first cavity 51 is provided between the upper inner shell 12 and the upper outer shell 11. A through hole 121 is opened in the upper inner shell 12 and a first resonant tube 31 and a second resonant tube 32 are provided. The through hole 121, the first resonant tube 31 and the second resonant tube 32 constitute a resonant hole, so that the first cavity 51 forms a Helmholtz resonant silencing cavity. The silencing is achieved through the Helmholtz resonant silencing cavity to eliminate noise at a specific frequency.

[0051] The second resonant tube 32 and the first resonant tube 31 are axially slidingly engaged, and the second resonant tube 32 can extend or retract axially relative to the first resonant tube 31. The driving device 4 is activated to drive the second resonant tube 32 to extend or retract a set length axially relative to the first resonant tube 31.

[0052] The second resonant tube 32 can extend or retract by a set length along the axial direction relative to the first resonant tube 31 to adjust and change the length of the resonant hole. The Helmholtz resonant silencing cavity changes the silencing frequency by adjusting the length of the resonant hole. Specifically, extending the length of the resonant hole lowers the silencing frequency, while shortening the length of the resonant hole increases the silencing frequency. This allows the real-time silencing frequency to match the peak frequency of the cavity noise generated by the peak excitation of the harmonic peak of the fundamental frequency corresponding to the real-time rotational speed of the compressor, thus achieving noise reduction.

[0053] The first resonant tube 31 has a limiting strip 311 arranged along the axial direction, and the second resonant tube 32 has a limiting groove 321 arranged along the axial direction. The limiting strip 311 slides into the limiting groove 321. This allows the second resonant tube 32 and the first resonant tube 31 to slide together along the axial direction.

[0054] The first resonant tube 31 is nested inside the second resonant tube 32, and the outer wall of the second resonant tube 32 has a spiral groove 322 along the axial direction. The drive device 4 is a motor, and the rotating end 41 of the motor has a protrusion 411. The motor is mounted on the upper inner shell 12, and the protrusion 411 engages with the spiral groove 322. Specifically, the upper edge of the first resonant tube 31 has a first flange 312, and the upper edge of the drive device 4 has a second flange 412. Screws 413 are used to sequentially assemble the second flange 412, the upper inner shell 12, and the first flange 312 to form a single unit. The rotating end 41 of the motor rotates forward or backward by a set angle, and through the engagement of the protrusion 411 and the spiral groove 322, it drives the second resonant tube 32 to extend or retract a set length relative to the first resonant tube 31 along the axial direction.

[0055] Currently, the shape of the compressor casing is generally close to that of a sphere, and the outline of the internal cavity is also close to that of a sphere. Various noises generated by the compressor core components and other components first reach the inner surface of the casing when they propagate outward. Since the inner surface is close to a sphere, the sound waves propagating in all directions are incident perpendicularly on the casing, without any effective refraction and noise reduction effect. The noise reduction can only be achieved by the sound insulation effect of the casing.

[0056] In this embodiment, the cavity volume of the anechoic shell is adjustable. The upper inner shell 12 has several protrusions 121 and recesses 122 formed on the side of the second cavity 52. ​​More specifically, the outer contours of the protrusions 121 and recesses 122 are stepped. The protrusions 121 and recesses 122 combine to form multiple angled wedge-like structures. When sound waves are incident on the surfaces of the upper inner shell 12 and the lower shell 2, they are refracted and reflected on the surfaces of the upper inner shell 12 and the lower shell 2. The angled wedge-like structures can refract noise multiple times and gradually attenuate the noise, thereby achieving refraction anechoication and reducing noise.

[0057] A compressor includes a core assembly 6, a frequency converter, and a controller. The compressor is equipped with a sound-absorbing housing with an adjustable resonant hole length as described above in this embodiment. The core assembly 6 is located inside the second cavity 52. ​​The controller is connected to the frequency converter and the drive device 4 via signal cables. The controller controls the operation of the drive device 4 according to the output frequency of the frequency converter.

[0058] A compressor noise reduction method is provided, using the compressor described above in this embodiment. The controller stores "the peak frequency of cavity noise generated by the peak excitation of the harmonic peak of the fundamental frequency corresponding to the compressor speed", "the quantitative relationship between the compressor speed and the inverter output frequency" and "the noise reduction frequency corresponding to the second resonant tube 32 extending or retracting a set length along the axial direction relative to the first resonant tube 31".

[0059] The method includes the following steps: the shape of the compressor's outer shell and the layout of its internal structure determine the internal cavity structure and volume. Given a fixed cavity structure and volume, its acoustic modal frequency can be determined. The cavity modal frequency can be accurately obtained by combining modal simulation and experimental testing.

[0060] After receiving the signal from the refrigerator's main control board, the compressor inverter controls the compressor to run at a specified speed. The controller reads the real-time output frequency of the inverter to obtain the real-time speed of the compressor, and then obtains "the peak frequency of the cavity noise generated by the peak excitation of the harmonic peak of the fundamental frequency corresponding to the real-time speed of the compressor".

[0061] By obtaining the compressor cavity modal frequency and the peak frequency of the harmonic of the real-time compressor speed corresponding to the fundamental frequency (i.e., the excitation frequency), the highest peak frequency of cavity noise at different speeds can be obtained. Since the cavity modal frequency is an inherent property and its frequency is constant, the excitation frequency corresponding to the compressor speed is different. When the excitation frequency is close to the cavity modal frequency, resonance amplification noise will be generated. The closer the excitation frequency is, the more obvious the resonance will be. Therefore, the frequency of the most obvious resonance at each speed, i.e., the peak frequency of cavity noise, can be calculated.

[0062] The peak noise reduction frequency of a Helmholtz resonant muffler is mainly affected by the resonant cavity volume, resonant hole length, diameter, and number. In this invention, the resonant cavity volume, resonant hole diameter, and number remain constant. The noise reduction frequency is adjusted by changing the resonant hole length; extending the resonant hole length lowers the noise reduction frequency, while shortening it increases it. Through simulation calculations and experimental tests, the noise reduction frequencies corresponding to different resonant hole lengths are determined in advance. Combined with the peak cavity noise frequency at each rotational speed, the optimal resonant hole length for that rotational speed can be obtained.

[0063] All the above parameters are embedded in the controller. When the compressor is working normally, the controller reads the real-time output frequency of the inverter to obtain the real-time speed of the compressor, obtains the peak frequency of the cavity noise, and then obtains the optimal resonant hole length. The controller controls the drive device 4 to move the second resonant tube 32 to extend or retract a set length along the axial direction relative to the first resonant tube 31, so as to achieve the optimal resonant hole length. This makes the real-time noise reduction frequency match the "peak frequency of cavity noise generated by the peak excitation of the harmonic peak of the fundamental frequency corresponding to the real-time speed of the compressor", thereby achieving adaptive noise reduction across the entire speed range and reducing cavity noise.

[0064] The present embodiment has been described in detail above with reference to the accompanying drawings. Based on the above description, those skilled in the art should have a clear understanding of the adjustable resonant hole length silencing housing, compressor, and silencing method of the present invention. The adjustable resonant hole length silencing housing, compressor, and silencing method of the present invention, by setting a first cavity 51, reduces the volume of the second cavity 52. ​​By reducing the volume of the second cavity 52, the cavity modal frequency of the second cavity 52 is increased, avoiding the excitation of resonance by the fundamental frequency's harmonics at lower peak frequencies near the cavity modal frequency of the second cavity 52. ​​The first cavity 51 is provided between the upper inner shell 12 and the upper outer shell 11, and a through hole 121 is opened in the upper inner shell 12, and a first resonant tube 31 and a second resonant tube 32 are provided. The through hole 121, the first resonant tube 31, and the second resonant tube 32 constitute a resonant hole, making the first cavity 51 form a Helmholtz resonant hole. The Helmholtz resonant silencing cavity achieves noise reduction. The second resonant tube 32 can extend or retract by a set length relative to the first resonant tube 31 along the axial direction to adjust the length of the resonant hole. By adjusting the length of the resonant hole, the silencing frequency is changed, so that the real-time silencing frequency matches the peak frequency of the harmonic of the fundamental frequency corresponding to the real-time speed of the compressor, thus achieving noise reduction. In addition, the upper inner shell 12 forms several protrusions 121 and recesses 122 on the side of the second cavity 52 to achieve refractive silencing. In addition to refractive silencing, sound insulation is further achieved through the upper inner shell 12 and the upper outer shell 11. Thus, through the reduction of cavity resonance noise, resonance silencing (the silencing frequency can be adjusted), refractive silencing, sound insulation of the upper inner shell 12 and the upper outer shell 11, the compressor achieves a good noise reduction effect.

[0065] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A noise-absorbing housing with adjustable resonant hole length, used in a compressor, characterized in that: It includes an upper outer shell, an upper inner shell, a lower shell, a first resonant tube, a second resonant tube, and a driving device; The upper inner shell is located inside the upper outer shell, the edge of the upper inner shell is connected to the edge of the upper outer shell, and a first cavity is left between the upper inner shell and the upper outer shell, the first cavity forming a Helmholtz resonance silencing cavity; The edge of the upper outer shell and / or the edge of the upper inner shell mates with the edge of the lower shell, and a second cavity is left between the upper inner shell and the lower shell; The upper inner shell has a through hole, which connects the first cavity and the second cavity; The first resonant tube is provided on the upper inner shell, and the first resonant tube is connected to the through hole; The second resonant tube is nested with the first resonant tube, and the second resonant tube and the first resonant tube slide together along the axial direction. The second resonant tube can extend or retract relative to the first resonant tube along the axial direction to adjust the effective length of the resonant hole formed by the through hole, the first resonant tube and the second resonant tube. The drive device is activated to cause the second resonant tube to extend or retract a set length relative to the first resonant tube along the axial direction. The upper inner shell forms several protrusions and recesses on one side of the second cavity. The outer contours of the protrusions and recesses are stepped. The protrusions and recesses combine to form multiple wedge-like structures with angles to form a refractive sound-absorbing structure.

2. The sound-absorbing housing with adjustable resonant hole length according to claim 1, characterized in that: A limiting strip is provided on the first resonant tube along the axial direction, and a limiting groove is provided on the second resonant tube along the axial direction. The limiting strip slides into the limiting groove.

3. The sound-absorbing housing with adjustable resonant hole length according to claim 1, characterized in that: The first resonant tube is nested inside the second resonant tube, and the outer wall of the second resonant tube has a spiral groove along the axial direction. The driving device is a motor, and the rotating end of the motor is provided with a protrusion; The motor is mounted on the upper inner shell, and the protrusion cooperates with the spiral groove; The rotating end of the motor rotates forward or backward by a set angle to drive the second resonant tube to extend or retract a set length relative to the first resonant tube along the axial direction.

4. The sound-absorbing housing with adjustable resonant hole length according to claim 1, characterized in that: The edge of the upper inner shell mates with the edge of the upper outer shell, and an annular groove is provided at the edge of the lower shell, with the edge of the upper outer shell fitting into the annular groove.

5. A compressor, comprising a core assembly, a frequency converter, and a controller, characterized in that: The compressor is equipped with a sound-absorbing housing with adjustable resonant hole length as described in any one of claims 1 to 4, the core assembly is located inside the second cavity, the controller is connected to the frequency converter and the drive device via signal cables, and the controller controls the operation of the drive device according to the output frequency of the frequency converter.

6. A compressor noise reduction method according to claim 5, characterized in that: The controller stores "the peak frequency of cavity noise generated by the peak excitation of the harmonic peak of the fundamental frequency corresponding to the compressor speed", "the quantitative relationship between the compressor speed and the inverter output frequency" and "the silencing frequency corresponding to the second resonant tube extending or retracting a set length along the axial direction relative to the first resonant tube". The method includes the following steps: When the compressor is running, the controller reads the real-time output frequency of the inverter to obtain the real-time speed of the compressor, and then obtains "the peak frequency of the cavity noise generated by the peak excitation of the harmonic peak of the fundamental frequency corresponding to the real-time speed of the compressor". The controller controls the drive device to move so that the second resonant tube extends or retracts a set length along the axial direction relative to the first resonant tube, so that the real-time noise reduction frequency matches the peak frequency of the cavity noise generated by the excitation of the harmonic peak of the fundamental frequency corresponding to the real-time rotational speed of the compressor.

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